If you are calling from an Orange contract mobile, o2, vodafone or Virgin (or one of the other networks like Tesco, Asda etc) you are unable to use Dialacode.
For these networks you may use our alternative service here Call 0207 access number using inclusive minutes with topuptotalk. Works on Vodafone, o2, Orange contract etc
This service works by texting CALLS4U to 83006, you are then given £3of calling credit from your mobile. You can use the service by calling the London access number 0207 124 6666 and enter your international number when asked to do so.
The London access number can be called with your free inclusive minutes. When your £3 credit runs out, you then send another text to top up. For more details see Call 0207 access number using inclusive minutes with topuptotalk. Works on Vodafone and o2
Orange PAYG users and T-Mobile can users CAN use Dialacode. Even though Orange own T-Mobile, the networks are independent and Orange contract is not approved to use Dialacode, only if you are PAYG. T-Mobile is approved, along with Three.